Each water quality class has what type of standard established?

Water quality classifications are established to ensure that different bodies of water meet specific standards for their intended uses, which can range from drinking water supply to recreational uses and habitat for aquatic life. Each of these classes encompasses various criteria that address multiple aspects of water quality.

Physical standards refer to characteristics such as temperature, turbidity, color, and total suspended solids, all of which can impact the usability and ecological integrity of the water. Chemical standards focus on the concentration of substances like nutrients (nitrogen and phosphorus), heavy metals, pH levels, and various pollutants. These chemical components are crucial for monitoring the health of the water and its suitability for different uses. Lastly, biological standards evaluate the presence and diversity of organisms in the water, such as bacteria, algae, and macroinvertebrates. These organisms can be indicators of the ecosystem's health and overall water quality.

By incorporating all these standards—physical, chemical, and biological—the water quality classification systems can provide a comprehensive understanding of water health, ensuring it meets necessary safety and ecological requirements. This holistic approach is why the correct answer includes all three types of standards.